Technical Field
The present disclosure relates to a driver. More particularly, the present disclosure relates to the driver for driving a power amplifier.
Description of Related Art
In general, a complete amplifier system may include an input signal converter, a small signal amplifier, a power amplifier and an output signal converter. For example, in a loudspeaker system of a classroom or of a meeting room, a microphone is the input signal converter utilized to convert an audio signal to an electrical signal, and then the small signal amplifier and the power amplifier amplify the electrical signal to drive a speaker, which is the output signal converter.
The small signal amplifier is basically utilized for linearly amplifying the weak electrical signal to make the electrical signal not to be distorted during the transmission to the power amplifier. In order to get the enough power for driving the output signal converter, the power amplifier is basically utilized to make the electrical signal obtain the current gain, and thus the power of the electrical signal is amplified.
However, in the design of the traditional signal amplifier, nonlinear amplification and distortion of the electrical signals are usually caused by the nonlinear characteristics of input capacitance of a transistor in a common source configuration. The traditional method to solve the problem is electrically coupling the transistor with another complementary transistor (e.g., N-type transistors are complementary to P-type transistors), and thus the nonlinear characteristic of the input capacitance can be eliminated by the complementary input capacitance, and the amplification of the electrical signal can be improved. However, the method increases the input capacitance and affects the driving ability of the small signal amplifier.